/*
 * Licensed to Elastic Search and Shay Banon under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. Elastic Search licenses this
 * file to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.langke.util.logging.support;

import java.util.HashMap;
import java.util.Map;

/**
 * @author kimchy (shay.banon)
 */
@SuppressWarnings("rawtypes")
public class LoggerMessageFormat {

	static final char DELIM_START = '{';
	static final char DELIM_STOP = '}';
	static final String DELIM_STR = "{}";
	private static final char ESCAPE_CHAR = '\\';

	public static String format(final String messagePattern,
			final Object... argArray) {
		return format(null, messagePattern, argArray);
	}

	public static String format(final String prefix,
			final String messagePattern, final Object... argArray) {
		if (messagePattern == null) {
			return null;
		}
		if (argArray == null) {
			if (prefix == null) {
				return messagePattern;
			} else {
				return prefix + messagePattern;
			}
		}
		int i = 0;
		int j;
		StringBuffer sbuf = new StringBuffer(messagePattern.length() + 50);
		if (prefix != null) {
			sbuf.append(prefix);
		}

		for (int L = 0; L < argArray.length; L++) {

			j = messagePattern.indexOf(DELIM_STR, i);

			if (j == -1) {
				// no more variables
				if (i == 0) { // this is a simple string
					return messagePattern;
				} else { // add the tail string which contains no variables and
							// return
					// the result.
					sbuf.append(messagePattern.substring(i,
							messagePattern.length()));
					return sbuf.toString();
				}
			} else {
				if (isEscapedDelimeter(messagePattern, j)) {
					if (!isDoubleEscaped(messagePattern, j)) {
						L--; // DELIM_START was escaped, thus should not be
								// incremented
						sbuf.append(messagePattern.substring(i, j - 1));
						sbuf.append(DELIM_START);
						i = j + 1;
					} else {
						// The escape character preceding the delimiter start is
						// itself escaped: "abc x:\\{}"
						// we have to consume one backward slash
						sbuf.append(messagePattern.substring(i, j - 1));
						deeplyAppendParameter(sbuf, argArray[L], new HashMap());
						i = j + 2;
					}
				} else {
					// normal case
					sbuf.append(messagePattern.substring(i, j));
					deeplyAppendParameter(sbuf, argArray[L], new HashMap());
					i = j + 2;
				}
			}
		}
		// append the characters following the last {} pair.
		sbuf.append(messagePattern.substring(i, messagePattern.length()));
		return sbuf.toString();
	}

	static boolean isEscapedDelimeter(String messagePattern,
			int delimeterStartIndex) {

		if (delimeterStartIndex == 0) {
			return false;
		}
		char potentialEscape = messagePattern.charAt(delimeterStartIndex - 1);
		if (potentialEscape == ESCAPE_CHAR) {
			return true;
		} else {
			return false;
		}
	}

	static boolean isDoubleEscaped(String messagePattern,
			int delimeterStartIndex) {
		if (delimeterStartIndex >= 2
				&& messagePattern.charAt(delimeterStartIndex - 2) == ESCAPE_CHAR) {
			return true;
		} else {
			return false;
		}
	}

	private static void deeplyAppendParameter(StringBuffer sbuf, Object o,
			Map seenMap) {
		if (o == null) {
			sbuf.append("null");
			return;
		}
		if (!o.getClass().isArray()) {
			safeObjectAppend(sbuf, o);
		} else {
			// check for primitive array types because they
			// unfortunately cannot be cast to Object[]
			if (o instanceof boolean[]) {
				booleanArrayAppend(sbuf, (boolean[]) o);
			} else if (o instanceof byte[]) {
				byteArrayAppend(sbuf, (byte[]) o);
			} else if (o instanceof char[]) {
				charArrayAppend(sbuf, (char[]) o);
			} else if (o instanceof short[]) {
				shortArrayAppend(sbuf, (short[]) o);
			} else if (o instanceof int[]) {
				intArrayAppend(sbuf, (int[]) o);
			} else if (o instanceof long[]) {
				longArrayAppend(sbuf, (long[]) o);
			} else if (o instanceof float[]) {
				floatArrayAppend(sbuf, (float[]) o);
			} else if (o instanceof double[]) {
				doubleArrayAppend(sbuf, (double[]) o);
			} else {
				objectArrayAppend(sbuf, (Object[]) o, seenMap);
			}
		}
	}

	private static void safeObjectAppend(StringBuffer sbuf, Object o) {
		try {
			String oAsString = o.toString();
			sbuf.append(oAsString);
		} catch (Throwable t) {
			System.err
					.println("Logger: Failed toString() invocation on an object of type ["
							+ o.getClass().getName() + "]");
			t.printStackTrace();
			sbuf.append("[FAILED toString()]");
		}

	}

	@SuppressWarnings("unchecked")
	private static void objectArrayAppend(StringBuffer sbuf, Object[] a,
			Map seenMap) {
		sbuf.append('[');
		if (!seenMap.containsKey(a)) {
			seenMap.put(a, null);
			final int len = a.length;
			for (int i = 0; i < len; i++) {
				deeplyAppendParameter(sbuf, a[i], seenMap);
				if (i != len - 1)
					sbuf.append(", ");
			}
			// allow repeats in siblings
			seenMap.remove(a);
		} else {
			sbuf.append("...");
		}
		sbuf.append(']');
	}

	private static void booleanArrayAppend(StringBuffer sbuf, boolean[] a) {
		sbuf.append('[');
		final int len = a.length;
		for (int i = 0; i < len; i++) {
			sbuf.append(a[i]);
			if (i != len - 1)
				sbuf.append(", ");
		}
		sbuf.append(']');
	}

	private static void byteArrayAppend(StringBuffer sbuf, byte[] a) {
		sbuf.append('[');
		final int len = a.length;
		for (int i = 0; i < len; i++) {
			sbuf.append(a[i]);
			if (i != len - 1)
				sbuf.append(", ");
		}
		sbuf.append(']');
	}

	private static void charArrayAppend(StringBuffer sbuf, char[] a) {
		sbuf.append('[');
		final int len = a.length;
		for (int i = 0; i < len; i++) {
			sbuf.append(a[i]);
			if (i != len - 1)
				sbuf.append(", ");
		}
		sbuf.append(']');
	}

	private static void shortArrayAppend(StringBuffer sbuf, short[] a) {
		sbuf.append('[');
		final int len = a.length;
		for (int i = 0; i < len; i++) {
			sbuf.append(a[i]);
			if (i != len - 1)
				sbuf.append(", ");
		}
		sbuf.append(']');
	}

	private static void intArrayAppend(StringBuffer sbuf, int[] a) {
		sbuf.append('[');
		final int len = a.length;
		for (int i = 0; i < len; i++) {
			sbuf.append(a[i]);
			if (i != len - 1)
				sbuf.append(", ");
		}
		sbuf.append(']');
	}

	private static void longArrayAppend(StringBuffer sbuf, long[] a) {
		sbuf.append('[');
		final int len = a.length;
		for (int i = 0; i < len; i++) {
			sbuf.append(a[i]);
			if (i != len - 1)
				sbuf.append(", ");
		}
		sbuf.append(']');
	}

	private static void floatArrayAppend(StringBuffer sbuf, float[] a) {
		sbuf.append('[');
		final int len = a.length;
		for (int i = 0; i < len; i++) {
			sbuf.append(a[i]);
			if (i != len - 1)
				sbuf.append(", ");
		}
		sbuf.append(']');
	}

	private static void doubleArrayAppend(StringBuffer sbuf, double[] a) {
		sbuf.append('[');
		final int len = a.length;
		for (int i = 0; i < len; i++) {
			sbuf.append(a[i]);
			if (i != len - 1)
				sbuf.append(", ");
		}
		sbuf.append(']');
	}
}
